N,N-Dimethylaniline → 2-Benzylthio-5-chloro-7-methyl[1,2,4]triazolo[1,5-a]pyridine

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Reaction Steps

N,N-Dimethylaniline (21.9 g, 0.18 mol) was added slowly to a mixture of 2-benzylthio-5-hydroxy-7-methyl[1,2,4]triazolo[1,5-a]pyridine (44.5 g, 0.164 mol) in 150 mL of phosphorus oxychloride with stirring. The mixture was heated at reflux with stirring for 20 hours. The excess phosphorus oxychloride was then removed by evaporation under reduced pressure. The residue obtained was dissolved in ethyl acetate, washed well with water and quickly concentrated by evaporation under reduced pressure to drive off the excess water. The residue was again dissolved in ethyl acetate and the resulting mixture was filtered with suction through a bed of silica gel. The filtrate was concentrated by evaporation under reduced pressure and the residue obtained was mixed with hexane. The resulting mixture was filtered to recover the solids and dried to obtain the 37.5 g (79 percent of theory) of the title compound as a tan powder melting at 108°-110° C.

Provenance & Evidence